\begin{table}%t3  
\caption{\label{tab:abundh}Relative abundances $n_{\xi} / n_{{\rm b}}$ of hydrogen species at redshifts $z=1000$, $z=100$ and $z=10$ in the SBBC model.}
%%\centering

\par
\begin{tabular}{l l l l l}
\hline
\hline
& & & SBBC &\\
\hline
Species && $z=1000$ & $z=100$ & $z=10$\\
\hline
$[{\rm H}]$ && 0.888 & 0.889 & 0.889\\
$[{\rm H}^+]$ && $8.5 \times 10^{-4}$ & $7.6 \times 10^{-5}$ & $5.8 \times 10^{-5}$\\
$[{\rm H}^-]$ && $5.7 \times 10^{-21}$ & $2.5 \times 10^{-15}$ & $7.2 \times 10^{-14}$\\
$[{\rm H_2}]$ && $1.2 \times 10^{-13}$ & $1.7 \times 10^{-7}$ & $2.7 \times 10^{-7}$\\
$[{\rm H_2}^+]$ &&7.7 $ \times 10^{-20}$ & $2.7 \times 10^{-14}$ & $6.7 \times 10^{-14}$\\
$[{\rm H_3}^+]$ &&3.0 $ \times 10^{-22}$ & $8.7 \times 10^{-17}$ & $8.4 \times 10^{-18}$\\
\hline
\end{tabular}
\end{table}